An influential theory of self-control holds that willpower is like a muscle — it is depleted through exertion, and it can be replenished by ingesting simple carbohydrates. There’s a book out now that explains this so-called “energy model” of willpower, at length — co-written by Roy Baumeister, one of its main academic proponents.

But some academic psychologists are now challenging the prevailing model of self-discipline. In one experiment, as Wray Herbert explains, in his Huffington Post column, test subjects whose willpower was stressed, and waning, got a boost by simply washing their mouths out with a sugar solution. The important point was they didn’t have to ingest the sugar to get the effect that some previous studies had attributed to refueling. So “what’s restoring self-control, if not metabolized carbs,” Herbert asks?